1. Field of the Invention
The present invention is related to the use of gossypol acetic acid as an anti-tumor agent effective against human cancers susceptible thereto.
2. Description of the Related Art
Gossypol is a double biphenolic compound derived from crude cottonseed oil which has been shown to inhibit spermatogenesis, and which has been used extensively as a male contraceptive in China.
While gossypol has been shown to retard the growth of some cancers in nude mice, its effects vary widely from species to species (Qian, SZ (1984) Ann. Rev. Pharmacol. Toxicol. 24: 329-60; Kim et al. (1984) Contraception 312: 5966-72). The effect of gossypol on the mitochondrial accumulation of rhodamine has been shown to be lower in magnitude in human cells than in rat testicular tumor cells (Tanphaichitr et al. (1984) Biol. of Reprod. 31: 1049-1060). Furthermore, closely related compounds such as mitotane (ortho-para'-DDD), a biphenolic compound which has been used to treat adrenal cancer, are only of limited effectiveness in treating cancer in humans. In addition, the side effects produced at the doses required for response can be debilitating, and include anorexia, nausea, vomiting, and dizziness. Conventional chemotherapy such as with cytoxan, adriamycin, 5FU, and other agents has a low response rate, and side effects such as hair loss, bone marrow suppression, nausea, vomiting, and heart failure. Clearly, an alternate or adjuvant therapy with less toxic side effects is desirable.
The use of gossypol and related compounds as anti-tumor agents against cancers in humans has yet to be reported.